I read somewhere earlier this week that Lukasz Fabianski was becoming frustrated by his lack of opportunities at Arsenal.

What can you say to that? On that performance, it’s some feat for him to have got any time on the pitch as Arsenal’s goalkeeper at all. When push came to shove – or should it be when slip came to slapstick – he once again fell short of what is expected from an Arsenal keeper. And sadly it’s merely the latest in a long line of howlers from him.

I don’t particularly want to make this a witch-hunt for a young keeper but when both conceded goals were at least in part down to him then you have to take him to task. The first goal was a simple slip-through-the-hands error. Awful and, for him, very embarrassing. There were mitigating circumstances in the second, but ignoring the ref’s rapid intervention and the way he seemed to get in the way of Campbell, it was still Fabianski who picked up the back pass and it was Fabianski who gave the ball back to the ref before the Arsenal defence had even sniffed the danger. Really naïve stuff.

There will now be those who wonder whether Fabianski has already sealed his own fate as an Arsenal prospect. Barring more Almunia injury woe, it already seems unlikely that he will play again this season. He does have a few things going for him though; namely Wenger’s patronage and his own youth.

Still, when we start seeing Almunia as some kind of goalkeeping demi-god by comparison, you know things are a bit screwy. Quite how we have assembled such a collection of substandard keepers is another matter entirely.

Enough of the negatives though, for with a better keeper, tonight could and should have ended differently. Although we were sloppy at times (in particular after their second goal), I thought we also showed some real attacking threat. Rosicky was very good on the right (and had a 100% nailed-on penalty waved away by the ref), Diaby was tricky until he faded, and Bendtner fought hard up front, having a few chances of his own.

All this with a pretty extensive injury list. For the return leg we’ll need some of the absentees back – that Song is now oodles better than Denilson is beyond dispute – but above all we’ll somehow, and I sigh a bit when I write this for the ninety billionth time, need to wipe out the incessant errors that have blighted this season.

Fabregas did not mince his words after the game when he said, “When you concede these goals you cannot go anywhere… schoolboy goal”.

So yes, it’s exasperating to have to report on another defeat, and another worrisome goalkeeping performance, but against the Porto side I saw tonight, I’m not trembling in my boots. They looked dangerous at times, but defensively they were like us – basically, porous – and at home, with an away goal, you’d have to say we stand a good chance of making it to the quarter-finals.

Looking beyond that is something of a lottery, but one thing is sure: if we continue to make rudimentary errors (tonight it was Fabianski but he’s hardly the first to have lost concentration this season) then we won’t be setting Madrid alight in May.